Content Revisions and disk space manaegement for download

A particular group of PCs is connected to the SEPM server thru' a WAN link of around 1.5Mbps and since it's shared, we need to control large files are not downloaded from servers.

Since virus defintions is are large files but in SEP 12.1.6, there is a feature content revisions and by default, number of revisions to keep is 42. So, I expect a PC should download the virus definitions in delta rather than full even if it's switched off for a week.

How can I verify the update of virus definitions of this particular PC, which's switched on again after being switched off for a week, can delta virus definitions updates instead of full? Can we check from any logs, events or else?

Thanks,